The Specific Force of Single Intact Extensor Digitorum Longus and Soleus Mouse Muscle Fibers...
González, E. ; Messi, M.L. ; Delbono, O.
2000-12-01 00:00:00
In the present study we measured, for the first time, the isometric specific force (SF, force normalized to cross sectional area) generated by single intact fibers from fast- (extensor digitorum longus, EDL) and slow-twitch (soleus) muscles from young adult (2–6), middle-aged (12–14) and old (20–24 month-old) mice. SF has also been measured in single intact flexor
digitorum brevis fibers from young mice. Muscle fibers have been classified into fast- or slow-twitch based on the contraction kinetics. Maximum SF recorded in EDL and soleus fibers from young and middle-aged mice did not differ significantly. A significant age-dependent decline in maximum SF was recorded in EDL and soleus fibers from young or middle-aged to old mice. The SF was 377 ± 18, 417 ± 20 and 279 ± 18 kPa for EDL fibers from young, middle-aged and old mice, respectively and 397 ± 17, 405 ± 24 and 320 ± 33 kPa for soleus fibers from age-matched mice, respectively. The frequency needed to elicit maximum force in EDL and soleus fibers from middle-aged to old mice did not differ significantly. In conclusion, the specific force developed by both fast and slow-twitch single intact muscle fibers declines with aging and more significantly in the former.
http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.pngThe Journal of Membrane BiologySpringer Journalshttp://www.deepdyve.com/lp/springer-journals/the-specific-force-of-single-intact-extensor-digitorum-longus-and-r1Rwb6njSK